To be able to purify the air in your home you need between 15 to 18 plants.
The plants should be between 6 to 8 inches in diameter for the containers which should purify the air in a 1,800 square foot home.
So to purify the air in one room you need at least 2 plants per room which should be enough to keep the air purified in the room.
Getting some fresh air into the room and house through opening windows is also another good idea because it's bad to keep your windows closed up all the time.
Fresh air coming into your home especially during spring after a long winter will help remove the germs from the house and remove dust as well and make it easier to breathe in your home.